Women who quit smoking for pregnancy are likely to resume tobacco smoking postpartum thereby placing themselves and their babies at risk. However, to date, tobacco interventions have not prevented sufficient numbers of women from relapsing postpartum. Thus, the postpartum period represents an important yet largely untapped opportunity to prevent the negative health consequences of smoking for women children. The proposed research builds on two threads of research by the investigators: 1) inquiry into the key role of weight concerns and mood in postpartum relapse prevention and 2) the use of enhanced Web-based interventions for health behavior change, generally, and tobacco cessation, specifically. Objectives: First, investigators propose to conduct formative work to develop an innovative, Enhanced Web+phone treatment designed to maintain tobacco abstinence postpartum. Then they will conduct a small randomized, controlled pilot feasibility study to assess the feasibility, acceptability, and initial efficacy of this novel, targeted, and tailored postpartum relapse prevention Web+phone intervention. Methods: In the first phase of this application, investigators propose to complete formative work involving postpartum women both in focus groups (n = 32) and in usability testing (n = 40) using an iterative treatment development process. In the second phase, investigators will conduct a pilot feasibility study in which 100 women who quit smoking for pregnancy and who want to remain nonsmokers postpartum will be randomly assigning to an Enhanced Web+phone intervention (n= 50) or a Basic Web Information Only control condition (n= 50). Women will be recruited by calls from research staff in late pregnancy using names and phone numbers provided by a commercial list service. Women will not be able to gain full access to the treatment program until after they have delivered. The proposed treatment program will be designed to be engaging, interactive, and tailored specifically to postpartum women. Measures: Assessment will focus on a) feasibility and acceptability of a Web-based tobacco abstinence maintenance program for postpartum women; b) efficacy of the intervention vs. the control in terms of tobacco use status; and c) exploratory analyses of putative underlying mechanisms (e.g., moderators, such as pre-pregnancy smoking rate, partner's tobacco use, and other demographic factors, and mediators, such as program usage, weight concerns, depressive symptoms, and perceived stress). Assessments will occur at baseline (via phone) and at three and six months postpartum (online). Non-responders will be called. Benefits: Postpartum women who maintain nonsmoking reduce risks of morbidity and mortality for themselves as well as protect the health of their baby. The development of a feasible and acceptable Web-based intervention to sustain tobacco abstinence could have substantial public health benefit because of its low cost and significant reach.